Ecology and Management of the Alfalfa Weevil (Coleoptera: Curculionidae) in Western United States Alfalfa

Alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), is a pest of concern in alfalfa (Medicago sativa L.) fields throughout the western United States. This introduced pest is most problematic in the early season causing defoliation and reduced hay yield and quality. Both adults and larvae feed on alfalfa, damaging terminals, foliage, and new crown shoots, but the larvae cause the majority of the damage. Three strains of alfalfa weevil, all H. postica, can be found in the western United States: the Western, Eastern, and Egyptian alfalfa weevil, H. brunnipennis (Boheman). Cultural, chemical, and biological control options are all viable strategies to include in an integrated management plan for alfalfa weevil, regardless of strain. We highlight research findings to best inform effective use of early harvest, grazing, insecticides, intercropping, and conservation biological control in alfalfa production systems.